Color cathode ray tube having a high-resolution electron gun

Abstract

A color cathode ray tube has an electron gun including a cathode structure for emitting three electron beams, a first electrode serving as a control electrode, a second electrode serving as an accelerating electrode and plural focus electrodes and an anode arranged in the order named, a phosphor screen composed of repeating patterns of three-color phosphor elements, a color selection electrode positioned the electron gun and the phosphor screen. The following inequalities are satisfied. {(L+1360xD-600)/280}<2>+{(P-0.16)/0.06}<2><=1, L+1360xD>=600, and P>=0.16, where D (mm) is a horizontal diameter of electron beam apertures in the first electrode, L (mm) is a distance from a midplane between the anode and one of the focus electrodes adjacent to, but spaced from the anode, to a center of the phosphor screen, and P (mm) is a horizontal center-to-center distance between a first phosphor element of a first color of the three-color phosphor elements in a first horizontal row of the repeating patterns and a second phosphor element of the first color which is nearest to the first phosphor element and is in a second horizontal row adjacent to the first horizontal row, at the center of the phosphor screen.

What is claimed is:  
     
       1. A color cathode ray tube comprising: 
       a vacuum envelope including a panel, a neck and a funnel for connecting said panel and said neck,  
       an electron gun housed in said neck and including a cathode structure for emitting three electron beams, a first electrode closely spaced from said cathode structure and serving as a control electrode, a second electrode serving as an accelerating electrode and a plurality of focus electrodes and an anode arranged in spaced relationship in a direction of travel of said three electron beams in the order named,  
       a phosphor screen formed on an inner surface of said panel and composed of repeating patterns of three-color phosphor elements facing said electron gun,  
       a color selection electrode positioned in said vacuum envelope between said electron gun and said phosphor screen, and  
       a deflection yoke mounted around said vacuum envelope for scanning said three electron beams on said phosphor screen;  
       the following inequalities being satisfied  
       
         
           {( L +1360 ×D− 600)/280} 2 +{( P −0.16)/0.06} 2 ≦1 , L +1360 ×D ≧600, and  
         
       
       
         
             P ≧0.16,  
         
       
       where D (mm) is a horizontal diameter of electron beam apertures in said first electrode, 
       L (mm) is a distance from a midplane between said anode and one of said plurality of said focus electrodes adjacent to, but spaced from said anode, to a center of said phosphor screen, and  
       P (mm) is a horizontal center-to-center distance between a first phosphor element of a first color of said three-color phosphor elements in a first horizontal row of said repeating patterns and a second phosphor element of said first color which is nearest to said first phosphor element and is in a second horizontal row adjacent to said first horizontal row, at said center of said phosphor screen.  
     
     
       2. A color cathode ray tube according to  claim 1 , wherein L≧260 mm and D≧0.25 mm. 
     
     
       3. A color cathode ray tube according to  claim 1 , wherein said electron beams resolve at least 4.4 dots/mm in a horizontal direction at said center of said phosphor screen, where the number of said dots in the horizontal direction is defined in terms of the number of trios of said three-color phosphor elements horizontally arranged in two adjacent horizontal rows. 
     
     
       4. A color cathode ray tube according to  claim 2 , wherein said electron beams resolve at least 4.4 dots/mm in a horizontal direction at said center of said phosphor screen, where the number of said dots in the horizontal direction is defined in terms of the number of trios of said three-color phosphor elements horizontally arranged in two adjacent horizontal rows.